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The global market for bone health foods is now worth US$2.5Bn, and is expected to grow at over 4% per annum1. Here DR. GERHARD GERSTNER, technical service manager special salts for Jungbunzlauer Ladenburg GmbH, discusses important technological as well as economical aspects of calcium fortification in dairy products with a focus on micronised tricalcium citrate DAIRY PRODUCTS: the calcium challenge
s everybody knows that dairy age of 50 are affected by an en- Calcium joins a range of products usually contain substantial hanced bone fragility and an increased fracture risk. ingredients that add value to Aamounts of calcium, they have been and During the conference, experts agreed to further in- dairy products still are an ideal food to be fortified with extra calcium crease efforts such as optimising diagnostics and treat- to meet nutritional needs by providing larger amounts ment and promoting adequate intake of calcium and in one single serving. vitamin D in the diet. However, the feasibility of calcium addition has to Looking at the ingredients list of dairy products, it be considered as technologically milk products repre- is evident that there is not a single source of calcium sent a complex food matrix. This challenge drives but rather a range of different possibilities which can mineral salt suppliers such as Jungbunzlauer to offer be used commercially: a range of different calcium salts to be able to tune ■ inorganic salts like calcium chloride, calcium car- them to food manufacturers’ applications: tricalcium bonate and calcium phosphate; citrate, calcium gluconate and the new product de- ■ milk minerals comprised mainly of calcium phos- velopment calcium lactate gluconate. phate; ■ organic salts like tricalcium citrate, calcium lactate, CALCIUM: A HOT TOPIC calcium lactate gluconate and calcium gluconate. Fighting osteoporosis and promoting calcium intake The selection of the appropriate calcium source for is a hot topic right now in Europe. At the Interna- a specific application is usually based on the consid- tional Osteoporosis Foundation conference in De- eration of a number of properties associated with the cember 2001, Health and Consumer Protection respective product such as solubility, calcium content,
Commissioner David Byrne emphasised his intention taste and bioavailability. Economic considerations are presents . to take action at EU level 2. another important factor. ‘Osteoporosis is a disease that is sadly overlooked, under-diagnosed and under-treated. This silent epi- SOLUBILITY VS. CALCIUM CONTENT demic affects millions of Europeans, causing human When fortifying liquid milk products, solubility, dis- suffering and taking a heavy economic toll,’ he said. solution characteristics and stability of ingredients in One in three woman and one in eight men over the solution are a major issue. There are calcium salts ᮣ
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FIG. 1: SOLUBILITY OF JUNGBUNZLAUER TRICALCIUM CITRATE IN WATER tripotassium citrate), and the use of stabilisers (e.g. carrageenan) as well as with the addition of flavour- ings. Tricalcium citrate is a very neutral tasting salt as 2,0 masking agents are not necessary. It is known that using highly soluble calcium salts 1,5 at high concentrations may lead to adverse effects in dairy applications4,5. The addition of mineral salts and especially of calcium has a strong impact on func- 1,0 tionality of milk products during processing and when 30˚ C consumed. Due to the fact that with higher soluble 60˚ C salts more free calcium ions are in solution and avail- 90˚ C 0,5 able for reaction than with lower soluble ones, com- Solubility TCC (g/L) plications in the form of calcium sediments can de- velop with time or when the product is heated during 0,0 manufacturing or in the household. This is the case, 4 5 6 7 8 9 if the natural milk components caseinate and phos- pH phate react with available calcium. Thus, although it might be easier to add highly sol- ᮤ with good solubility like calcium gluconate, cal- uble calcium salts rather than tricalcium citrate to cium lactate, and calcium lactate gluconate but their milk products, higher amounts of calcium might be drawback is a comparably low calcium content (9- difficult to achieve without control of pH and addi- 13% calcium). The inorganic calcium chloride (36% tion of chelating agents such as potassium citrate 4,5. calcium) displays good solubility, but its use is re- Since the particle size and solubility are linked with stricted due to its bitter and salty taste. Other inor- mouthfeel properties, Jungbunzlauer has developed ganic calcium salts with a high calcium content like micronized grades for tricalcium citrate combining calcium carbonate and calcium phosphate (38-40% excellent dispersion characteristics with a neutral taste calcium), on the other hand, are poorly soluble. profile. Tricalcium citrate offers a good combination: The commonly used tetrahydrate form shows a high cal- BIOAVAILABILITY cium level (21%) and moderate solubility (0.9 g/L). Any nutrient’s effectiveness depends on its bioavail- Tricalcium citrate shows improved solubility at pH- ability, which means how well the human body ab- values below 4.5 as found in fruit preparations used sorbs and utilises it. On average, only about 10 to for fruity milk products. Contrary to other salts, tri- 30 % of calcium is absorbed from a mixed diet by calcium citrate is better soluble at low temperatures healthy adults6 . Several different factors influence this which can be an advantage for cold food processing level, among which the type of salt which provides the (Fig 1). calcium. Various scientific studies have shown that or- To further increase the solubility and ease of dis- ganic calcium salts outperform inorganic calcium persion, Jungbunzlauer has developed a particularly sources such as calcium carbonate and calcium phos- fine (micronized) tricalcium citrate grade. With this phate with regard to their relative bioavailability. Tri- special granulation of min. 90% < 20 µm, it can be calcium citrate, calcium gluconate and calcium lactate suspended in milk or whey drinks and high concen- gluconate all belong to the highly-bioavailable organic trations of calcium (eg, 1.6 g Ca/L) can be reached sources, as shown by extensive human and animal without negative taste effects. studies4..
TASTE AND MOUTHFEEL ECONOMIC CONSIDERATIONS VS. Generally, high levels of calcium, particularly insolu- CALCIUM CONTENT ble forms like carbonates and phosphates, tend to Although inorganic calcium salts are cheaper than or- produce a chalky mouthfeel and may promote astrin- ganic ones due to their low price and high calcium gency or bitter taste in the finished product. Calcium content, they are not used in fortified milk products lactate may impart some bitter notes at high concen- to a large extent. Comparing the mainly used organic trations, comparable to characteristics found for cal- sources on the other hand, they are all in the same cium chloride3 . price range, except for the premium calcium sources Calcium carbonate may come across as soapy or calcium lactate gluconate and the milk minerals. lemony. Calcium phosphate has a bland flavour, but For this reason, the wide range of calcium contents imparts a gritty mouthfeel. Negative effects of cal- of calcium gluconate (9%), calcium lactate (13%) and cium on taste can be masked with chelating agents (eg tricalcium citrate (21%) has a considerable impact on
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FIG. 2: MAKING OF MILK DRINK, CREAM CHEESE PREPARATION AND DESSERT FORTIFIED WITH MICRONISED TRICALCIUM CITRATE
Low fat milk, buttermilk, whey product, Cream cheese, sugar Low fat milk, cream, sugar, sugar, fruit juices, glucose syrup, flavour cocoa powder, flavour +Tricalcium Citrate M 2090 +Tricalcium Citrate M 2090 +Tricalcium Citrate M 7090 Cold stirring Cold stirring Cold stirring
Stabiliser Fruit Thickening carrageenan preparation agents Pasteurising Pasteurising Pasteurising
Fortified milk drink: Fortified cream cheese preparation: Fortified dessert: 20% calcium RDI in 100 ml 16% calcium RDI in 100 g 15% calcium RDI in 100 g the raw material cost when the price of calcium added calcium have advantages, if they do not impart a gritty is calculated for the product to be fortified. Among mouthfeel. Ultra-fine Tricalcium Citrate M 2090 can the organic salts with high bioavailability and more be added prior pasteurisation of the milk. After inoc- neutral taste profiles, tricalcium citrate (21% calcium) ulation and incubation, the resulting plain yoghurt clearly stands out as the most economic option for cal- contains eg, 200mg calcium/100 g (25 % calcium cium addition and is the main choice for milk prod- RDI) without significant negative consequences on ucts. firmness or syneresis. This fortified plain yoghurt can be used as such or APPLICATIONS also as a suitable intermediate product in order to The described characteristics of micronised tricalcium maintain a high calcium level in the final yoghurt citrate makes it an ideal calcium salt for all kinds of even after ingredients low in calcium (such as fruits) applications of calcium-fortified dairy products. Some had been added. relevant examples are given below. By adding extra calcium, these products can be fortified to higher lev- FORTIFICATION OF MILK DRINKS els or simply readjusted to the calcium levels of milk AND DESSERTS where processing (e.g. in cottage cheese) or addition Fortification of these products with tricalcium citrate of ingredients with low/no calcium (eg cocoa, fruits, is not a difficult task (Fig 2). The ultra-fine Trical- sugar) lead to a decrease of calcium content. cium Citrate M 2090 can be added with the other To achieve a stable suspension in liquid milk prod- dry ingredients, e.g. via a Venturi blender to the prod- ucts within seconds, a jet mixer (e.g. Ytron-Y, Ytron uct stream, usually at cold temperatures (6-8°C). Germany) can be used at 50°C. This temperature is There is no particular sequence to be followed, how- recommended for mixing to avoid damage to the fat ever ingredients increasing viscosity such as thicken- matrix of the milk. With conventional stirrers, ho- ing agents are added preferably at the end directly be- mogeneous dispersion of tricalcium citrate will take fore pasteurisation. longer, but can be done at cold temperatures (6-8°C). FORTIFICATION OF CREAM CHEESE PRODUCTS FORTIFICATION OF YOGHURTS If fruits are used for cream cheese or also for yoghurt Plain yoghurt contains 120mg calcium per 100g products, an indirect addition of tricalcium citrate to (15% calcium Recommended Daily Intake, RDI), the milk product via the fruit preparation might be which is equivalent to the level of milk. Addition of the optimum solution (Fig 2). Fruit preparations gen- highly soluble calcium salts (calcium gluconate, cal- erally have a low pH and high citric acid/fruit acid cium lactate) prior to fermentation had been studied concentration which has a positive effect on solubility by American and Turkish researchers7-9. Several nega- and dispersibility of tricalcium citrate. tive effects had been found, such as lack of heat sta- In this application it is therefore possible to use Tri- bility of the calcium-fortified milk blend to be used calcium Citrate M 7090 which is also a micronised for inoculation and negative consequences on the fer- grade, but with a less strict particle size limit (min. 90 mentation period and on sensory scores. % < 70 µm) compared to M 2090 (max. 90% > 20 For fortification of yoghurt, lower soluble forms of µm). Besides the fortification aspect, tricalcium ᮣ
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ᮤ INFORMATION citrate has also a positive stabilising influence in the tial source of this important mineral. By adding extra fruit preparation. Calcium pectinate bridges are built calcium in the form of organic calcium salts, dairy up and improve the firmness of the fruit texture. products can be fortified to higher levels and provide
Europe individuals who choose not to consume large Phone +41 61 295 5100 FORTIFICATION OF COTTAGE CHEESE amounts of dairy products to meet their daily re- Fax +41 61 295 5108 Cottage cheese usually contains 60 mg/100 g of quirements in one or two servings. Email [email protected] calcium in the creamed form and only 32 mg/100 g Calcium salts are also used to simply readjust the USA in the dry curd form compared to 120mg calcium in product to the calcium levels of milk where process- Phone +1 800 828 0062 milk. However, cottage cheese is popular as a low-fat ing or addition of low-calcium ingredients lead to a Fax +1 617 964 2921 and high quality protein food. To increase the nutri- decrease of calcium contents. Combined functional Email [email protected] tional value, calcium salts can be added to the curd foods, such as food where prebiotic fibres and cal- right after setting as demonstrated in studies done at cium had been added are seen to be the next step in Ohio State University 10. Calcium levels of up to calcium fortification which further optimises calcium 200mg/100g could be reached, but the overall qual- intake, exploiting the synergistic effect between e.g. in- ity was inferior to the control. ulin and calcium on calcium absorption. Recent studies about calcium as well as fibre and in- The challenge for milk products manufacturers is to ulin enrichment of cottage cheese had been done at provide a product having high calcium content with Arla Foods, Sweden11. Jungbunzlauer tricalcium cit- good taste and appealing properties. rate M 2090 had been selected because of its neutral Since micronised tricalcium citrate is available, it taste properties in this application. has replaced inorganic as well as organic salts in ex- The technologists’ aim was to reach at least 15% of isting dairy applications. An important explanation the Swedish calcium RDI (120 mg of 800 mg) in 100 from the technological standpoint is that especially in g of a creamed cottage cheese. In this case, calcium the milk matrix, a highly dispersible calcium salt has was not added to the curd process, but to the dress- advantages over highly soluble alternatives. ing which is mixed with the curds at the end. Tricalcium citrate M 2090 was added to a mixture REFERENCES of skimmed milk, cream and salt which was stirred at 1. Leatherhead Food International, UK, Press Release 8°C for 15 min total. The fortified milk was then No. 827 (2002) heated to 50°C and inulin + citrus fibres added at 2. EU Press Release Memo/01/416, Brussels, 12/2001 lower stirring rate. Finally, the mixture was ho- 3. Tordoff, M.G. Some basic physophysics of calcium mogenised and pasteurised. At the end, this dressing salt solutions. Chemical Senses 21, 417-424 (1996) with extra calcium was added to the curds to obtain 4. Flynn, A.; Cashman, K. Calcium. In: Hurrel, R. the fortified cottage cheese product. (ed.) The Mineral Fortification of Foods, Leatherhead To assess the influence of processing on taste prop- Food International, UK, (1999) erties and final calcium content in the dressing, para- 5. Reddy, S.; Sher, A.; Van Vadehra, D.; Wredal, meters such as fat content (0.3 vs. 9 % w/w), ho- E.R. Calcium complex and a process of making a food mogenising pressure (20 vs. 120 bar), and inulin con- fortified with calcium. US Patent 5,928,691 (1999) centration (0.5 vs. 3,4 % w/w) had been varied. Good 6. National Research Council. Calcium, In: Recom- results with 16 % calcium RDI in 100 g could be ob- mended Dietary Allowances: 10th edition. Washington tained at high fat content, high pressure and low in- D.C.; National Academy Press, 174-184 (1989) ulin content. Optimum results (17 % RDI) were 7. Fligner, K.; Lindamoood, J.B.; Hansen, P.M.T. found at high fat content, high pressure, and high in- Fortification of low-fat plain yogurt with calcium glu- ulin concentration. conate. Cultured Dairy Products J. 23, 5-9 (1988) Taste panel tests revealed that the fortified creamed 8. Yousef, A.E.; Rusli, M. Modification of starter cul- cottage cheese did not show off flavours with calcium ture for production of calcium fortified yogurt. Cultured concentrations of 17 % RDI. As addition of inulin in- Dairy Products Journal 30, 20-25 (1995) creases absorption of calcium significantly, this ‘bi- 9. Pirkul, T.; Temiz, A.; Erdem, Y.K. Fortification of functional’ food can serve as an even better source to yoghurt with calcium salts and its effect on starter mi- fight calcium deficiency. croorganisms and yoghurt quality. Int. Dairy J. 7, 547- 552 (1997) CONCLUSIONS 10. Martin, J.H.; Zullo, P.A. Methods for increasing Consumers increasingly prefer food with added nutri- calcium in cottage cheese. Cultured Dairy Products J. tional value rather than taking nutritional supple- 26, 11-18 (1991) ments to fill up their calcium needs. Dairy products 11. Sabine Remling and Eva Ekman, Arla Foods Swe- VISIT OUR WEBSITE: are seen to be one of the best means to help fighting den and Chalmers University of Technology, Sweden, www.ifi-online.com calcium deficiency as they are known to be a substan- personal communication (2002) IFI
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